Molding apparatus and process

ABSTRACT

A molding process ( 100 ) comprising the step of inserting an uncured blank ( 102 ) in a mold cavity ( 14 ) formed in a mold system, the uncured blank including fiber and uncured binder, transferring heat from the mold system to a cool pressurized gas ( 108 ) to establish a hot pressurized gas, injecting the hot pressurized gas into the mold cavity ( 110 ), and transferring heat ( 112 ) from the hot pressurized gas to the uncured blank to cause the uncured binder to cure and establish a cured product ( 114 ).

CROSS-REFERENCE TO RELATED FILES

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application Ser. No. 61/625,888, filed Apr. 18, 2012, and toU.S. Provisional Application Ser. No. 61/779,713, filed Mar. 13, 2013,both of which are expressly incorporated by reference herein.

BACKGROUND

The present disclosure relates to a process for making an insulationproduct, and particularly to a molding process. More particularly, thepresent disclosure relates to a molding process for making an insulationproduct where binder included in the insulation product is cured duringthe molding process.

SUMMARY

A mold for manufacturing a cured product may include a first mold tooland a second mold tool. The second mold tool may be coupled to the firstmold tool to move relative to the first mold tool between an openedposition and a closed position in which a mold cavity is formed betweenthe first and second mold tools when the second mold tool is in theclosed position.

In some embodiments, a molding system may include a first mold unit anda second mold unit. The second mold unit may move relative to the firstmold unit between an opened position and a closed position in which amold cavity may be formed between the first and second mold units whenthe second mold unit is in the closed position. The second mold unit maybe coupled to a heat source to cause the second mold unit to have amolding temperature. The molding temperature may be configured to cure abinder included in an uncured blank.

In some embodiments, the first mold unit may be formed to include apassageway in fluid connection with a source of pressurized gas. Thefirst mold unit may further be formed to include an array of holesformed in the first mold unit that are arranged to open into thepassageway to cause pressurized gas to be communicated from thepassageway to the mold cavity when the second mold unit is in the closedposition. As the pressurized gas flows through the passageway, heat maybe transferred from the mold unit to the pressurized gas to cause a hotpressurized gas to be established prior to the hot pressurized gasentering the mold cavity.

In some embodiments, the second mold unit may be formed to include apassageway in fluid connection with a source of pressurized gas. Thesecond mold unit may be further formed to include an array of holesformed in the second mold unit that are arranged to open into thepassageway to cause pressurized gas to be communicated from thepassageway to the mold cavity when the second mold unit is in the closedposition. As the pressurized gas flows through the passageway, heat maybe transferred from the mold unit to the pressurized gas to cause a hotpressurized gas to be established prior to the hot pressurized gasentering the mold cavity.

In some embodiments, the first and second mold units may each be formedto include a passageway in fluid connection with a source of pressurizedgas. Each mold unit may be further formed to include an array of holesthat are arranged to open into the passageway of each mold unit to causepressurized gas to be communicated from each passageway to the moldcavity when the mold units are in the closed position. As thepressurized gas flows through the passageways, heat may be transferredfrom the mold units to the pressurized gas to cause hot pressurized gasto be established prior to the hot pressurized gas entering the moldcavity.

In some embodiments, the hot pressurized gas may have a hot-gastemperature. The hot-gas temperature may be about equal to the moldingtemperature. The hot-gas temperature may be at least about 100 degreesFahrenheit, for example at least: about 120 degrees Fahrenheit, about150 degrees Fahrenheit, about 200 degrees Fahrenheit, about 250 degreesFahrenheit, or about 300 degrees Fahrenheit. The hot-gas temperature maybe no more than about 500 degrees Fahrenheit, for example no more than:about 450 degrees Fahrenheit, about 400 degrees Fahrenheit, or about 350degrees Fahrenheit.

In some embodiments, the passage may include a perimeter portion and adistribution portion. The perimeter portion may be arranged to extendaround a perimeter of the second mold unit to cause heat to betransferred from the second mold unit to the pressurized gas toestablish the hot pressurized gas. The distribution portion may be influid communication with the perimeter portion and in fluidcommunication with the array of holes to cause the hot pressurized gasto be delivered to the mold cavity. The passageway may be configured tocause the hot-gas temperature of the hot pressurized gas to be achievedprior to the hot pressurized gas moving through the array of holes.

In some embodiments, the pressurized gas may have a cold-gastemperature. The cold-gas temperature may be about equal to roomtemperature. The cold-gas temperature may be no more than about 80degrees Fahrenheit, for example no more than: about 70 degreesFahrenheit, or about 60 degrees Fahrenheit. The cold-gas temperature maybe at least about 50 degrees Fahrenheit, for example at least about 40degrees Fahrenheit.

A molding process may include several steps. The molding process mayinclude a step of inserting an uncured blank in a mold cavity formed ina mold system. The uncured blank may include fiber and uncured binder,

In some embodiments, the molding process may include a step oftransferring heat from the mold system to a cool pressurized gas toestablish a hot pressurized gas. The molding process may include a stepof injecting the hot pressurized gas into the mold cavity.

In some embodiments, the molding process may include a step oftransferring heat from the hot pressurized gas to the uncured blank tocause the uncured binder to cure and establish a cured product. Themolding process may include a step of transferring heat from the moldsystem to the uncured blank to cause uncured binder to cure.

In some embodiments, the uncured binder may be substantially free offormaldehyde. The binder may be based on a carbohydratecomponent/nitrogen-containing component binder system, i.e. thecarbohydrate component(s) and nitrogen-containing component(s) may bethe major components of the uncured binder. Accordingly, the totalamount of the at least one carbohydrate component and the at least onenitrogen-containing component in the uncured binder by dry weight may beat least 20 wt.-%, based on the total weight of the uncured binder. Forexample, the total amount of the at least one carbohydrate component andthe at least one nitrogen-containing component by dry weight of theuncured binder may be at least 30 wt.-%, 40 wt.-%, 50 wt.-%, 60 wt.-%,70 wt.-%, 80 wt.-%, 90 wt.-%, 95 wt.-%, or 98 wt.-%.

The amount of binder present by weight in the molded product, expressedas Loss on Ignition (LOI), may be no more than about 25%, for example nomore than: about 20% or about 18%; it may be at least 5%, for example atleast: about 8%, about 10% or about 12%.

The cycle time to produce a molded product may be no more than about 10minutes, for example, no more than: about 9 minutes, about 8 minutes,about 7 minutes, about 6 minutes, or about 5 minutes. The cycle time maybe at least about 30 seconds, for example at least: about 60 seconds orabout 90 seconds.

The cycle time to produce a shape-molded product may be no more thanabout 10 minutes, for example, no more than: about 9 minutes, about 8minutes, about 7 minutes, about 6 minutes, or about 5 minutes. The cycletime may be at least about 30 seconds, for example at least: about 60seconds or about 90 seconds.

The molded product may be a mineral wool insulation product, for examplea glass wool or stone wool insulation product. The cured product mayhave a thermal conductivity of no more than about 0.04 W/mK, for exampleno more than: about 0.035 W/mK or about 0.033 W/mK. The cured productmay by an acoustical mineral insulation product.

The molded product may have a thickness of at least about ⅛ inch, forexample at least: about ¼ inch, about ¾ inch, or about one inch. Themolded product may have a thickness of no more than about four inches,for example no more than: about three inches, about 2.5 inches, or about2.25 inches.

The molded product may have a density of at least about 0.6 pounds percubic foot, for example at least: about one pound per cubic foot, about1.2 pounds per cubic foot, or about 1.6 pounds per cubic foot. Themolded product may have a density of no more than about 13 pounds percubic foot, for example no more than: about 10 pounds per cubic foot,about 8 pounds per cubic foot, or about 6 pounds per cubic foot.

Additional features of the present disclosure will become apparent tothose skilled in the art upon consideration of illustrative embodimentsexemplifying the best mode of carrying out the disclosure as presentlyperceived.

BRIEF DESCRIPTIONS OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is diagrammatic view of a molding process in accordance with thepresent disclosure;

FIG. 2 is perspective view of a simplified mold tool in accordance withthe present disclosure showing an array of 1/16 of an inch holes formedin an inner surface of the mold tool for hot air to flow into a moldcavity and suggesting that the mold tool is heated by an externalsource;

FIG. 3 is a partial perspective view of the mold tool of FIG. 2 showinga series of passageways drilled into the mold tool in a patternconfigured to provide sufficient time for heat to be transferred to coldpressurized gas introduced into the passageways along a front rightcorner of the mold tool so that a hot pressurized gas flows through thearray of holes formed in the inner surface of the mold tool;

FIG. 4 is a perspective view of a heated platen in accordance with thepresent disclosure showing an array of holes formed in an inner surfaceof the platen for communicating a hot gas into an uncured part;

FIG. 5 is a partial perspective view of the electrically heated platenof FIG. 4 showing a series of grooves formed in the platen that areconfigured to receive associated electric heaters therein to heat theplaten;

FIG. 6 is a partial perspective view of the heated platen of FIGS. 4 and5 showing a series of air passageways drilled into the platen that areconfigured to communicate hot gas through holes and into the uncuredpart and that the series of passageways are located between the groovesformed in the platen for electric heaters;

FIG. 7 is a partial perspective view of the heated platen of FIGS. 4-6showing that a heating passageway is formed in the heated platen whichreceives cold pressurized gas at a bottom left of the heated platen andmoves the cold pressurized gas along a perimeter of the platen totransfer heat to the cold pressurized gas to provide the hot pressurizedgas before the hot pressurized gas is communicated to the airpassageways and through the holes;

FIG. 8 is a graph showing temperature vs. time for several thermocouples(symbols) embedded in a molded part molded in a test mold tool assuggested in FIG. 9 and showing computational fluid dynamics model datafor each corresponding location shown as a solid line with a color ofeach line matching a color of each symbol;

FIG. 9 is plan view of a test mold tool showing locations for eachthermocouple used to prepare the graph of FIG. 8;

FIG. 10 is a photograph of a simulation showing temperatures at variouslocations in a sample mold tool during computational fluid dynamicsmodeling after about ten seconds;

FIG. 11 is a view similar to FIG. 10 after about 30 seconds;

FIG. 12 is a view similar to FIG. 11 after about 60 seconds;

FIG. 13 is a view similar to FIG. 12 after about 210 seconds;

FIG. 14 is a photograph of a simulation showing fluid velocities on acenter plane taken through the uncured product during computationalfluid dynamics modeling after about 30 seconds;

FIG. 15 is a photograph of a simulation showing molded part temperatureson the center plane during computational fluid dynamics modeling afterabout 30 seconds;

FIG. 16 is a photograph of a simulation showing hot gas temperatures onthe center plane during computational fluid dynamics modeling afterabout 30 seconds;

FIG. 17 is a photograph of a simulation showing gas temperatures as thegas moves through the passageways formed in the test mold duringcomputational fluid dynamics modeling after about 353 seconds; and

FIG. 18 is a photograph of a simulation showing gas velocities as thegas moves through the passageways formed in the test mold tool duringcomputational fluid dynamics modeling after about 353 seconds.

DETAILED DESCRIPTION

A molding system 10 in accordance with the present disclosure includes afirst mold unit 11 and a second mold unit 12 as suggested in FIGS. 2-7.Together, the first and second mold units 11, 12 cooperate to define amold cavity 14 there between that is formed in the molding system.During a molding process 100, an uncured product is located between themold units 11, 12 in the mold cavity 14 where heat and pressure areapplied to the uncured product to provide a cured product as shown inFIG. 1. The uncured product includes uncured binder and fibers. In oneexample, the fibers are glass.

Each mold unit 11, 12 is formed to include an inner surface 20configured to engage and mate with the uncured product and provide ashape to the cured product. Each mold unit 11, 12 is formed to include apassageway 22 through which a pressurized gas is communicated thereto asshown in FIGS. 3 and 7. An array 24 of holes is formed in the innersurface 20 of each mold unit 11, 12 and each hole is arranged to openinto the passageway 22 to allow the pressurized gas to move from a gassource, through the passageway 22, out of the array 24 of holes, andinto the mold cavity 14.

In one example, the mold unit 11 is a platen 11P used to form relativelyflat cured products as suggested in FIGS. 4-7. In another example, themold unit 11 is a tool 11T used to form contoured or curved curedproducts as suggested in FIGS. 2 and 3. The mold unit 11 is made, forexample, of metal and heated so that the mold unit 11 remains hotthroughout the molding process 100.

In an example of use, pressurized gas is provided by a gas source at arelatively cool temperature. The cool temperature may be about 70degrees Fahrenheit. The pressurized gas is provided to the passageway 22where the gas moves through a perimeter portion 22P of the passagewaywhich extends along a perimeter 26 of the mold unit as suggested inFIGS. 3 and 7. As the pressurized gas moves along the perimeter portion22P of the passageway 22, heat from the mold unit 11 is transferred tothe pressurized gas to provide a hot pressurized gas that is thenadmitted to a distribution portion 22D of the passageway as shown inFIGS. 3 and 7. The hot gas is then discharged from the distributionportion 22D through the array 24 of holes into the uncured productlocated in the mold cavity 14.

Uncured binder included in the uncured product is cured through theapplication of heat so that a cured product is provided. Heat istransferred to the uncured product by conduction from the mold unit 11and through convection from the hot gas. In one example, an uncuredproduct, labeled Sample 1 in Table 1 below, is cured in a mold unit byonly conduction in about 7.1 minutes.

In comparison, the same uncured product is cured in the same mold unitusing conduction and convection in about 2.0 minutes. In Sample 1, thebinder used in the uncured product is a substantially formaldehyde-freebinder. The addition of convective heat transfer via the hot gas causesat least a 70% decrease in cycle time when using a substantiallyformaldehyde-free binder.

Examples of formaldehyde-free binders and their chemistry are describedin U.S. Pat. Nos. 7,854,980 B2, 5,977,232, 7,803,879, 6,699,945,5,318,990, 6,194,512, PCT publication PCT/US2006/028929, U.S.application Ser. Nos. 11/675,413, 12/599,858, WO2011/138459 A1 andW02011/022668, EP1 732968, Patent Applications EP2386394 andEP2199332A1, Patent Applications US2009/0275699, and 2007/0292619 (eachof which is incorporated by reference herein).

In comparison, another uncured product, labeled Sample 4 in Table 1below, is cured in a mold unit by only conduction in about threeminutes. In comparison, the same uncured product is cured in the samemold unit using conduction and convection in about 1.5 minutes. InSample 4, the binder used in the uncured product is phenol-formaldehyde(PF) binder which may cure faster at lower temperatures. The addition ofconvective heat transfer via the hot gas causes at least a 50% decreasein cycle time when using a PF binder.

TABLE 1 Comparison of cycle times to full cure of an uncured product forvarious product types and binder types. Cycle time (min) Full Cure FullCure No with Convection Convection Sample Heating Heating 1Formaldehyde-Free Binder, 16/9 7.10 2.00 (top/bottom) holes/sq.ft., 4lb/cubic foot density, 15% LOI, 1 inch Loft, 380 degrees Fahrenheit,staggered hole locations, 6 scfm per mold tool, 12 scfm total 2Formaldehyde-Free Binder, 16/9 7.1 1.5 (top/bottom) holes/sq.ft., 4lb/cubic foot density, 15% LOI, 1 inch Loft, 380 degrees Fahrenheit,staggered hold locations 12 scfm top mold tool, 10 scfm bottom moldtool, 22 scfm total 3 Formaldehyde-Free Binder, 7.1 1.2 177/177(top/bottom) holes/sq.ft., 4 lb/cubic foot density, 15% LOI, 1 inchLoft, 380 degrees Fahrenheit, aligned hole locations, 12 scfm per moldtool, 24 scfm total 4 PF Binder, 16/9 (top/bottom) 3.00 1.50holes/sq.ft., 4 lb/cubic foot density, 15% LOI, 1 inch Loft, 380 degreesFahrenheit, 6 scfm per mold tool, 12 scfm total

A molding process 100 in accordance with the present disclosure uses themolding system 10 of the present disclosure as shown in FIG. 1. Themolding process 100 includes several operations that provide a hot gasto an uncured blank located in the mold cavity 14 of the mold system tocause curing of uncured binder included in the uncured blank to be curedvia convective heat transfer from the hot gas to the uncured blank.

In the example, the uncured blank includes an outer trim layer, a firstblanket, a second blanket, and an inner trim layer. Each blanket is madeof a substrate and an uncured binder. In one example, the substrate is afiber. For example, the fiber is glass, cellulose, or mineral wool. Instill yet another example, the substrate may be a laminate or a veneer.For example, the laminate or veneer is a wood chip or wood particle. Inaddition, the uncured blank may have any number of blankets and trimlayers. In addition, the uncured blank may include a thermoplasticlayer, also called an interleaf, located between each neighboring pairof blankets to interconnect the neighboring pairs of blankets. Thethermoplastic layer may also be located between the trim layer and theblanket.

As shown in FIG. 1, the molding process 100 begins with an operation 102in which an uncured blank is inserted into the mold cavity 14 of themolding system 10. The molding process 100 then proceeds to an operation104 in which the molding system 10 is moved to the closed positiontrapping the uncured blank in the mold cavity 14. The molding process100 then proceeds to an operation 106 in which heat is transferred fromthe inner surface 20 of the mold system 28 to the uncured blank viaconductive heat transfer to begin curing the binder included in theuncured blank as suggested in FIG. 1.

The molding process 100 then proceeds to an operation 108 in which heatis transferred from the molding system 10 to a cool pressurized gas toestablish a hot pressurized gas as suggested in FIG. 1. The coolpressurized gas, for example, has a temperature of about 74 degreesFahrenheit. In another example, the cool pressurized gas has atemperature similar to room temperature. The hot pressurized gas, forexample, has a temperature of about 100 degrees Fahrenheit to about 300degrees Fahrenheit. In another example, the hot pressurized gas has atemperature of about 300 degrees Fahrenheit to about 500 degreesFahrenheit.

Once the hot pressurized gas is established, the molding process 100proceeds to an operation 110 as shown in FIG. 1. During the operation110, the hot pressurized gas is injected through the array 24 of holesformed in the inner surface 20 into the mold cavity of the moldingsystem 10.

The molding process 100 then proceeds to an operation 112 in which heatfrom the hot pressurized gas is transferred from the hot pressurized gasto the uncured blank via convective heat transfer. As a result, uncuredbinder included in the uncured blank is cured at a relatively fasterrate than the conductive heat transfer alone. In one example, the array24 of holes may be configured to move more hot pressurized gas throughspecific areas of the uncured blank that may require increased heatflux.

The molding process 100 then proceeds to an operation 114 in which thecured product is established. The cured product has had sufficient heattransferred to the uncured blank to cause substantially all of thebinder to be cured.

The molding process 100 then proceeds to an operation 116 in which thepressurized gas is vented from the mold cavity 14. Venting may occur onthe other mold unit 11, 12 if only one mold unit 11, 12 includes thearray 24 of holes. Venting may also occur on an edge of the mold systemas described earlier. Venting may also be continuous or intermittent.Venting through a perimeter of the cured product minimizes the risk offouling of the array 24 of holes and the passageway 22 in the mold units11, 12 due to condensate formation and minimizes the need for cleaningand maintenance.

The molding process 100 then proceeds to an operation 118 in which themolding system 10 is opened to allow access to the mold cavity 14. Theprocess then proceeds to an operation 120 in which the cured product isremoved from the mold cavity 14 as suggested in FIG. 1.

The molding process 100 may be used with existing infrastructure. As aresult, capital costs may be minimized when implementing the moldingprocess 100. For example, an existing mold tool may be drilled to formthe passageways and holes so that pressurized gas may be heated andtransferred to the mold cavity.

The molding process 100 also provides for even curing of the binderincluded in the uncured blank. The molding process 100 achieves thisresult by minimizing a temperature gradient between the surfacetemperature of the inner surface 20 of the molding system 10 and thecore temperature of the cured product. In addition, the entire uncuredblank may heat up evenly with minimal temperature variations. As aresult hot and cold spots in the uncured blank may be minimized.

The molding process 100 may also provide for dimensionally stable curedproducts with maximized through-put and reliability. The molding process100 also provides for consistently fully cured products. The curedproducts are formed in a mold system with a minimum cycle timeregardless of product variations (product density, binder distribution,binder gobs, binder wet spots, etc.) The molding process 100 also isconfigured to provide cured products including a non-permeable membraneor barrier.

In a modified molding process, the molding process 100 may be used toshape mold the uncured blank. Shape molding is a process by which theuncured blank is intentionally only partly cured. The degree of cure isgenerally chosen to ensure that the uncured blank retains its shape fromthe molding system 10 and satisfies all dimensional requirements whenthe shaped product is removed from the mold cavity 14. Some portions ofa shaped product, typically portions in the core, are not fully cured.The shape-molded part is subjected to a subsequent secondary curingprocess to ensure full cure.

As an example, the shape-molding process allows for relatively shortcycle times and simplified design of the array 24 of holes. It was foundthat the molding process 100 provides for relatively short shape-moldingtimes. The shaped products are then subjected to a secondary curingprocess, for instance heating the parts in-line or in a batch. It wasfound that the secondary curing step is a suitable process to obtainconsistently cured products independent of product variations (i.e.variations of product density, wet spots, binder globs, etc.)

In one example, the mold units 11, 12 are platens. Platens are large,flat, heated plates that come together to apply pressure and heat to theuncured blank. The platens may be heated from an external source such asan oil heater. However, some are heated using electrical resistance. Inthe example of oil heat, the hot oil is pumped through passages in theplaten and then returned to the heater. With either oil or electricheat, it should be possible to form the passageway 22 in the platens forpassing the pressurized air into the mold cavity 14.

In another example, the mold units 11, 12 may be mold tools used toproduce a shaped product other than a flat panel. Mold tools may beheated with hot oil, with electrical resistance, heated platens, or anycombination thereof. The biggest difference between a platen and a moldtool is that the company that is molding parts will have the mold toolsmade to meet the dimensions and requirements of the part where as aplaten is manufactured by the press manufacturer and is simpler indesign and more straight forward in its ability to transfer heat.

The pressurized gas is passed through the passageway 22 and heat istransferred to the pressurized gas to establish a hot pressurized gas.The pressurized gas is provided by a source which may be regulated. Thepressurized gas may be compressed air, for example, compressed airsupplied at a relative pressure of greater than about 15 pounds persquare inch, for example greater than: about 30 pounds per square inchor 46 pounds per square inch and/or less than about 140 pounds persquare inch, for example less than about: 120 pounds per square inch or100 pounds per square inch. The pressurized gas may be provided by ablower. The source should provide sufficient pressure to the pressurizedgas to move the pressurized gas through the passageway 22, the array 24of holes, and the uncured blank. However, the pressure should be limitedso as not to damage the uncured blank.

In an example of use, the pressurized air flow is switched off when themolding system 10 is in the opened position and is not turned back onuntil the molding system 10 has returned to the closed position. Inorder to minimize cure cycle time and deformation of the cured product,the air flow may be increased gradually from low velocity to highvelocity from start to end of the cure cycle. Steam may also be usedinstead of air. In the example of steam, initially some condensate maybe formed within the cured product. The condensate may be removed byextending mold cycle time or a secondary heating process.

The molding process 100 and molding system 10 provide several surprisingresults. One surprising result is that despite the array 24 of holes andthe passageway 22 not necessarily having even heat flow, the curedproducts show a relatively even cure and do not have localized coldspots. Another surprising result is that the molding process 100provides cured products even when the uncured blank has portions thatare relatively very dense that normally restrict air flow. Still yetanother surprising result is that molding process 100 may be used withcured products including a membrane located in the middle of the curedproduct that may operate to restrict air flow. Another surprising resultis that the molding process 100 and molding system 10 may be used tofully cure cured products in relatively very short cycle times as shownin Table 2 below. Finally, another surprising result is that the moldingprocess 100 provides the cured product even when the cured productincludes relatively heat sensitive materials.

TABLE 2 Comparison of cycle times to full cure of an uncured product forvarious product types and binder types with and without shape molding.Cycle time (min) Shape Shape Full Cure Full Cure Molding No Molding withNo with Convection Convection Convection Convection Sample HeatingHeating Heating Heating 1 Formaldehyde-Free Binder, 5.5 1.0 7.1 2.0 16/9(top/bottom) holes/sq.ft., 4 lb/cubic foot density, 15% LOI, 1 inchLoft, 380 degrees Fahrenheit, staggered hole locations, 6 scfm per moldtool, 12 scfm total 2 Formaldehyde-Free Binder, 5.5 1.0 7.1 1.5 16/9(top/bottom) holes/sq.ft., 4 lb/cubic foot density, 15% LOI, 1 inchLoft, 380 degrees Fahrenheit, staggered hold locations 12 scfm top moldtool, 10 scfm bottom mold tool, 22 scfm total 3 Formaldehyde-FreeBinder, 5.5 7.1 1.2 177/177 (top/bottom) holes/sq.ft., 4 lb/cubic footdensity, 15% LOI, 1 inch Loft, 380 degrees Fahrenheit, aligned holelocations, 12 scfm per mold tool, 24 scfm total 4 PF Binder, 16/9(top/bottom) 3.0 1.0 >3.0 1.5 holes/sq.ft., 4 lb/cubic foot density, 15%LOI, 1 inch Loft, 380 degrees Fahrenheit, 6 scfm per mold tool, 12 scfmtotal

The molding process 100 may include flow control elements to control theflow of the pressurized gas. As a result, heat transfer may beoptimized.

Various binder chemistries may be used as part of the molding processesdescribed herein. Furthermore, temperature sensitivity of the curedproducts may also be taken into account. While temperatures of theplatens or mold tools may be increased to provide shorter cycle times,temperatures are limited to those temperatures where decomposition ofthe binder, the trim layer, the facing materials, and the cured productdoes not occur due to excessive heat.

In addition, existing platens and mold tools may be retrofitted toperform according the molding process 100 and establish the moldingsystem 10 of the present disclosure. As a result, capital costs forimplementing the molding process are minimized while obtaining minimizedcycle time and the use of various binders.

Flow distribution of hot gas through the molded part may be optimized.Optimization may include optimizing the pattern of holes, hole size, andhole locations.

Cross flow through the uncured blank is possible. Cross flow may be usedwhen a perimeter of the cured product is extremely dense. Extremedensity at the perimeter edge may occur due to a pinched edge, forexample.

Cycle time is reduced as a result of blowing, for example, air throughheated platens or mold tools rather than blowing hot air through anunheated platen or tool. In addition, blowing hot air through anunheated platen or mold tool is needed to keep the platen or mold toolhot while the platen or mold tool is open. If this is not done, theplaten or mold tool may cool and a longer cycle time may be needed. As aresult of passing hot air through an unheated mold unit, energyefficiency is reduced.

The mold units 11, 12 may be formed to include the passageway 22. Thepassageway 22 may take on various shapes or patterns as may be neededfor specific platen or mold unit 11, 12 designs. The passageway 22includes a minimum passageway length that is a factor of desired gasflow rate, tool temperature, and required hot-gas temperature. In oneillustrative example shown in FIGS. 3 and 7, the passageway 22 is formedalong a perimeter of the mold tool (FIG. 3) and a perimeter of theplaten (FIG. 7). After the cool gas is moved through the perimeterportion of the passageway 22, sufficient heat may have been transferredfrom the mold units 11, 12 to provide a hot gas having an evenlydistributed temperature throughout before the hot gas moves through adistribution portion 22D of the passageway 22.

In one example, the passageway 22 is formed in a mold tool which iscoupled to a platen to move therewith. The platen is formed to includean electrical or oil-based heating system which provides heat to themold tool. However, the tool may be formed to include an electrical oroil-based heating system in addition to the air passageway as suggestedin FIGS. 2-7.

A platen may be formed with a routing path for heating elements as shownin FIG. 5. The heating elements may be electrical pencil heaters. Eachelectrical pencil heater may be spaced apart from each neighboringelectrical pencil a distance of about two inches to about six inches. Inanother example, a platen may be heated with hot oil that flows througha serpentine or snake-like channel system (plug flow, re-circulatingheated oil). In another example, heating elements may be included in atool where heat is transferred to the tool from a platen to compensatefor locations in the tool where heating is uneven. Heating may be unevenas a result of having a large distance between the heated platen and theinner surface of the mold tool.

In some examples, heated platens may be used in place of mold tools whenmolding flat panel parts. Flat panel parts include, for example, panelsused in office cubical walls. When platens are used to mold parts,heating elements and gas passageways may both be located in the platens.The location of both relative to each other can vary in a wide range,but proper heat transfer to the cold pressurized gas should beconsidered.

In instances where parts have curve(s) or are non-flat, mold tools maybe used. Non-flat parts include, for example, hood liners forautomobiles.

The array 24 of holes formed in the inner surface 20 of the mold units11, 12 are shown, for example, in FIGS. 2 and 4. The distance betweeneach hole and a neighboring hole in the array of holes may vary. In oneexample, the distance is about 0.5 inches to about six inches. Inanother example, the distance is about one inch to about three inches.

In one example, the array of holes 24 for providing the hot pressurizedgas may be formed only on one mold tool. A separate array of holes maybe formed on the opposite mold tool to vent the pressurized gas after itpasses through the uncured blank.

In another example, the array 24 of holes for providing the hotpressurized gas may be present on both mold tools. As a result, thepressurized gas may be vented along a perimeter of the uncured blank.Perimeter venting may be used where an uncured blank has a high densityalong a perimeter causing a high pressure drop of the hot gas. Theperimeter edge may be perforated to minimize flow resistance andpressure drop.

The diameter of each hole in the array of holes may be dependent uponproduct appearance as dimpling by high velocity gas or embossingtextures in high density areas of the molded part should be minimized.In one example, holes may have a diameter of about 1/64 of an inch toabout 1/16 inch. In another example, vented set screws may be formedwith a hole having a diameter of about 0.042 inches to about 0.156inches. The diameter of holes included in the array of holes may beconstant throughout or the diameter may vary from hole to hole.

A cured product in accordance with the present disclosure may be usedfor sound absorption or as a thermal shield. Sound absorption may bedesired in flat architectural applications (i.e. wall system for officespaces and theatres) and contoured parts in automotive applications(i.e. hood liners). Some molded parts are used in Original EquipmentManufacturers (OEM) equipment for sound absorption (HVAC equipment,clothes washers, clothes dryers, dishwashers, etc.)

A cured product may have a width of about one inch to about six feet. Acured product may have a length of about two inches to about twelvefeet. The cured product may have a thickness of about ⅛ of an inch toabout two inches in one example. In another example, the cured productmay have a thickness less than ⅛ of an inch and greater than two inches.The cured product may have a density of about 1 pound per cubic foot toabout 50 pounds per cubic foot. In addition, the density of the curedproduct may vary throughout the cured product.

The cured product may be subjected to a molding temperature when thebinder included in the molded part is being cured. The moldingtemperature may vary according to the fibers and binder used in themolded part. Each binder may have a different minimum moldingtemperature at which the binder cures. A maximum molding temperature isestablished at the point in which decomposition, melting, and thermalinstability of the fibers, binder, and trim layers occurs. In oneillustrative example, the molding temperature is about 200 degreesFahrenheit to about 500 degrees Fahrenheit. As a result, the hot gas hasa hot-gas temperature of about 200 degrees Fahrenheit to about 500degrees Fahrenheit.

A sample mold tool including six thermocouples TC1, TC2, TC3, TC4, TC5,TC6 was used for testing and modeling heat transfer and temperatures ofa sample molded part and is shown in FIG. 9. During a test, an outersurface of each mold tool was heated to about 400 degrees Fahrenheit.Cool air flowing at a rate of about 16.8 scfm and about 74 degreesFahrenheit was admitted to the mold tools to flow through the mold tooland absorb heat from the tool. The change in temperature for eachthermocouple TC1, TC2, TC3, TC4, TC5, TC6 is shown over a time span ofabout 210 seconds in a graph shown in FIG. 8. Also, a computationalfluid dynamics model of the test mold tool and molded part was preparedand the results are shown as solid lines on the graph of FIG. 8. Eachthermocouple TC1, TC2, TC3, TC4, TC5, TC6 is shown as a different symbolhaving a different color. The modeled temperatures are shown with colorsmatching the associated thermocouple locations. In general, both theoverall trend of the model and the test match; indicating predictable,reproducible results as suggested in FIG. 8.

1. A mold system comprising a first mold unit and a second mold unit coupled to the first mold unit to move relative to the first mold unit between a closed position in which a mold cavity is defined between the first and the second mold units and an opened position in which the second mold unit is spaced apart from the first mold unit, the second mold unit is coupled to a heat source to cause the second mold unit to be at a molding temperature, wherein the second mold unit is formed to include a passageway in fluid connection with a source of pressurized gas and an array of holes formed in the second mold unit that are arranged to open into the passageway to cause pressurized gas to be communicated from the passageway to the mold cavity when the second mold unit is in the closed position, the pressurized gas flows through the passageway absorbing heat from the second mold unit to cause a hot pressurized gas to be established prior to the hot pressurized gas entering the mold cavity.
 2. The mold system of claim 1, wherein the hot pressurized gas has a hot-gas temperature about equal to the molding temperature.
 3. The mold system of claim 1, wherein the passage includes a perimeter portion and a distribution portion, the perimeter portion is arranged to extend around a perimeter of the second mold unit to cause heat to be transferred from the second mold unit to the pressurized gas to the hot pressurized gas, and the distribution portion is in fluid communication with the perimeter portion and in fluid communication with the array of holes to cause the hot pressurized gas to be delivered to the mold cavity.
 4. The mold system of claim 1, wherein the passageway is configured to cause the hot-gas temperature of the hot pressurized gas to be provided prior to the hot pressurized gas moving through the array of holes.
 5. The mold system of claim 1, wherein the pressurized gas has a cold-gas temperature and the cold-gas temperature is about equal to room temperature.
 6. The mold system of claim 1, wherein the first mold unit is coupled to a heat source to cause the first mold unit to be at the molding temperature and wherein the first mold unit is formed to include a passageway in fluid connection with the source of pressurized gas and an array of holes is formed in the first mold unit that are arranged to open into the passageway to cause pressurized gas to be communicated from the passageway to the mold cavity when the second mold unit is in the closed position to cause heat to be transferred from the first mold unit to the pressurized gas to cause the hot pressurized gas to be established prior to the hot pressurized gas entering the mold cavity.
 7. The mold system of claim 1, wherein the hot pressurized gas is vented through a perimeter of the mold system after the hot pressurized gas has moved through the mold cavity.
 8. The mold system of claim 1, wherein each hole in the array of holes of the first mold unit is aligned with an associated hole in the array of holes in the second mold unit to cause the array of holes in the first mold unit to be a mirror of the array of holes in the second mold unit.
 9. The mold system of claim 1, wherein the array of holes of the first mold unit is offset from the array of holes of the second mold unit to cause convective heat transfer from the hot pressurized gas to be maximized.
 10. The mold system of claim 1, wherein the first mold unit is formed to include a vent passageway in fluid connection with atmosphere surrounding the mold system and an array of vent holes formed in the first mold unit that are arranged to open into the vent passageway to cause the hot pressurized gas to be communicated from mold cavity to the vent passageway after the hot pressurized gas moves through the mold cavity.
 11. The mold system of claim 1, wherein the pressurized gas is air.
 12. The mold system of claim 1, wherein the pressurized gas is steam.
 13. The mold system of claim 12, wherein the steam is superheated.
 14. The molding system of claim 1, wherein the hot pressurized gas has a pressure and flow rate configured to minimize dimpling and deformation of an uncured blank in the mold cavity.
 15. A molding process comprising the step of inserting an uncured blank in a mold cavity formed in a mold system, the uncured blank including fiber and uncured binder, transferring heat from the mold system to a cool pressurized gas to establish a hot pressurized gas, injecting the hot pressurized gas into the mold cavity, and transferring heat from the hot pressurized gas to the uncured blank to cause the uncured binder to cure and establish a cured product.
 16. The molding process of claim 15, further comprising the steps of transferring heat from the mold system to the uncured blank to cause uncured binder to cure.
 17. The molding process of claim 15, wherein the uncured binder is substantially free of formaldehyde.
 18. The molding process of claim 15, wherein the hot pressurized gas has a hot-gas temperature of about 100 degrees Fahrenheit to about 300 degrees Fahrenheit.
 19. The molding process of claim 15, wherein the hot pressurized gas has a hot-gas temperature of about 200 degrees Fahrenheit to about 500 degrees Fahrenheit.
 20. The molding process of claim 15, wherein in the pressurized gas has a pressure and flow rate configured to minimize dimpling and deformation of an uncured blank in the mold cavity. 